All week, the wavelength of the visible light spectrum in the range of 380nm~760nm, is a human eye can feel the seven colours-red, Orange, yellow, green, cyan, blue, violet, but the seven colors of light is a single color of light.
For example, the red LED peak wavelength of 565nm. No white light in the visible light spectrum, because white light is not monochromatic, but synthesis of composite from various monochromatic light, just as the Sun is made from seven monochromatic white light, and color TVs in the white light is composed of three primary colors red, green, and blue synthetic.
Thus, issued to LED white light, it should include the spectral characteristics of the entire visible spectrum. But to do this performance LED, process is not possible. According to the study of visible light, human eyes can see white light would take at least two hybrid, two-wavelength light (blue + yellow light) or three-wavelength light (blue + green + red light) mode. These two patterns of white light, blue light is needed, so get the blue light has become the key technologies of manufacturing white, the current largest LED manufacturing company to chase the "Blu-ray". International Master "Blu" manufacturers only have a few, so white LED application, especially high brightness white light LED in China there is a process.